HRLib – sinusoid/noise separation in audio signals.

HRLib library, developed by Olivier Gillet, is a C implementation of a sinusoid/noise separation method from Roland Badeau’s Thesis [1]. A graphical interface permits to perform separation and mix of separated tracks in real time.

The audio signal is decomposed into a sum of exponentially damped sinusoids (EDS) and autoregressive noise. This decomposition is based on the high-resolution subspace method ESPRIT. Initially, the signal is pre-accentuated, and then decomposed into sub-bands. In each channel, the noise autoregressive envelope is estimated, and the signal is whitened with a FIR Filter [1].

It uses the ESTER method [2] to estimate the number of sinusoids, and a fast adaptive algorithm (Sequential Iteration) for subspace tracking [3]. Sinusoids/noise separation is performed by projection onto the signal subspace and the noise subspace [4], and by reconstruction with the synthesis filter bank.